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MBio Oct 2023Before environmental opportunistic pathogens can infect humans, they must first successfully grow and compete with other microbes in nature, often via secreted...
Before environmental opportunistic pathogens can infect humans, they must first successfully grow and compete with other microbes in nature, often via secreted antimicrobials. We previously discovered that the bacterium , the causative agent of Legionnaires' disease, can compete with other microbes via a secreted molecule called HGA. Curiously, strains that produce HGA is not wholly immune to its toxicity, making it a mystery how these bacteria can withstand the "friendly fire" of potentially self-targeting antimicrobials during inter-bacterial battles. Here, we identify several strategies that allow the high-density bacterial populations that secrete HGA to tolerate its effects. Our study clarifies how HGA works. It also points to some explanations of why it is difficult to disinfect from the built environment and prevent disease outbreaks.
Topics: Humans; Legionella pneumophila; Legionnaires' Disease
PubMed: 37728338
DOI: 10.1128/mbio.01207-23 -
BMJ (Clinical Research Ed.) Oct 2023
Topics: Humans; Refugees; Drowning; Legionnaires' Disease; Ships; Stress Disorders, Post-Traumatic
PubMed: 37798012
DOI: 10.1136/bmj.p2290 -
Metabolites Jul 2023() is a common etiological agent of bacterial pneumonia that causes Legionnaires' disease (LD). The bacterial membrane-associated virulence factor macrophage...
() is a common etiological agent of bacterial pneumonia that causes Legionnaires' disease (LD). The bacterial membrane-associated virulence factor macrophage infectivity potentiator (Mip) exhibits peptidyl-prolyl--isomerase (PPIase) activity and contributes to the intra- and extracellular pathogenicity of . Though Mip influences disease outcome, little is known about the metabolic consequences of altered Mip activity during infections. Here, we established a metabolic workflow and applied mass spectrometry approaches to decipher how Mip activity influences metabolism and pathogenicity. Impaired Mip activity in genetically engineered strains decreases intracellular replication in cellular infection assays, confirming the contribution of Mip for pathogenicity. We observed that genetic and chemical alteration of Mip using the PPIase inhibitors rapamycin and FK506 induces metabolic reprogramming in , specifically branched-chain amino acid (BCAA) metabolism. Rapamycin also inhibits PPIase activity of mammalian FK506 binding proteins, and we observed that rapamycin induces a distinct metabolic signature in human macrophages compared to bacteria, suggesting potential involvement of Mip in normal bacteria and in infection. Our metabolic studies link Mip to alterations in BCAA metabolism and may help to decipher novel disease mechanisms associated with LD.
PubMed: 37512541
DOI: 10.3390/metabo13070834 -
International Journal of Environmental... Sep 2023Travel-associated Legionnaires' disease is a significant public health concern worldwide. A high number of cases are reported every year among travellers who stay at...
Travel-associated Legionnaires' disease is a significant public health concern worldwide. A high number of cases are reported every year among travellers who stay at guest houses, hotels, and spas. Indeed, hot water systems, showers, and air-conditioning systems can be contaminated by , which grows at 25-42 °C. Studies have shown that in Sardinia, especially during the summer months, the water circulation in the hotels' pipes is exposed to extremely high temperatures. As a result, this study was conducted to assess the colonization of hotel water systems by in Sardinia, concerning a recent EU directive 2020/2184 for drinking water with a limit of 1000 CFU /L. Methods. A total of 112 accommodation facilities were analyzed, of which 61.3% were found to be colonized with , and out of a total of 807 samples, 32.5% were positive for presence. The results showed a higher number of positive samples in the summer season. This was also associated with the higher concentration presence of >1000 CFU/L in the samples. Consequently, this study confirms that local hotel operators should improve their water safety and prevention plans, especially in spring and summer.
PubMed: 37754582
DOI: 10.3390/ijerph20186722 -
Epidemiology and Infection Jan 2024Legionellosis is a disease caused by the bacterium that most commonly presents as Legionnaires' disease (LD), a severe form of pneumonia. From 2015 to 2019, an average...
Legionellosis is a disease caused by the bacterium that most commonly presents as Legionnaires' disease (LD), a severe form of pneumonia. From 2015 to 2019, an average of 438 LD cases per year were reported in Canada. However, it is believed that the actual number of cases is much higher, since LD may be underdiagnosed and underreported. The purpose of this study was to develop an estimate of the true incidence of illnesses, hospitalizations, and deaths associated with LD in Canada. Values were derived using a stochastic model, based on Canadian surveillance data from 2015 to 2019, which were scaled up to account for underdiagnosis and underreporting. Overall, there were an estimated 1,113 (90% CrI: 737-1,730) illnesses, 1,008 (90% CrI: 271-2,244) hospitalizations, and 34 (90% CrI: 4-86) deaths due to domestically acquired waterborne LD annually in Canada from 2015 to 2019. It was further estimated that only 36% of illnesses and 39% of hospitalizations and deaths were captured in surveillance, and that 22% of illnesses were caused by serogroups and species other than serogroup 1 (non-Lp1). This study highlights the true burden and areas for improvement in Canada's surveillance and detection of LD.
Topics: Humans; Legionnaires' Disease; Canada; Legionella pneumophila; Legionellosis; Legionella; Cost of Illness
PubMed: 38204334
DOI: 10.1017/S0950268824000013 -
Frontiers in Cellular and Infection... 2024, one of the main pathogens that causes community-acquired pneumonia, can lead to , a condition characterized predominantly by severe pneumonia. This disease, caused by...
, one of the main pathogens that causes community-acquired pneumonia, can lead to , a condition characterized predominantly by severe pneumonia. This disease, caused by the bacterium , can quickly progress to critical pneumonia and is often associated with damage to multiple organs. As a result, it requires close attention in terms of clinical diagnosis and treatment. Omadacycline, a new type of tetracycline derivative belonging to the aminomethylcycline class of antibiotics, is a semi-synthetic compound derived from minocycline. Its key structural feature, the aminomethyl modification, allows omadacycline to overcome bacterial resistance and broadens its range of effectiveness against bacteria. Clinical studies have demonstrated that omadacycline is not metabolized in the body, and patients with hepatic and renal dysfunction do not need to adjust their dosage. This paper reports a case of successful treatment of with omadacycline in a patient who initially did not respond to empirical treatment with moxifloxacin. The patient also experienced electrolyte disturbance, as well as dysfunction in the liver and kidneys, delirium, and other related psychiatric symptoms.
Topics: Humans; Tetracyclines; Anti-Bacterial Agents; Legionnaires' Disease; Legionella pneumophila; Treatment Outcome; Male; Community-Acquired Infections; Moxifloxacin; Middle Aged
PubMed: 38836055
DOI: 10.3389/fcimb.2024.1380312 -
Emerging Infectious Diseases May 2024We investigated molecular evolution and spatiotemporal dynamics of atypical Legionella pneumophila serogroup 1 sequence type 1905 and determined its long-term...
We investigated molecular evolution and spatiotemporal dynamics of atypical Legionella pneumophila serogroup 1 sequence type 1905 and determined its long-term persistence and linkage to human disease in dispersed locations, far beyond the large 2014 outbreak epicenter in Portugal. Our finding highlights the need for public health interventions to prevent further disease spread.
Topics: Legionella pneumophila; Portugal; Humans; Legionnaires' Disease; Spatio-Temporal Analysis; Evolution, Molecular; Disease Outbreaks; History, 21st Century; Recurrence; Phylogeny; Serogroup
PubMed: 38666647
DOI: 10.3201/eid3005.231383 -
Cureus May 2024Legionnaires' disease is a potentially severe type of pneumonia most often caused by the organism . Exposure to this bacterial pathogen typically happens in the...
Legionnaires' disease is a potentially severe type of pneumonia most often caused by the organism . Exposure to this bacterial pathogen typically happens in the community but may also occur in the hospital setting. This report describes the case of a patient who presented due to 10 days of fever, shortness of breath, and diarrhea, with initial imaging demonstrating multifocal pneumonia. The patient was appropriately started on empiric antibiotics for community-acquired pneumonia and admitted to the medicine floor. The patient showed no meaningful improvement in his initial hospital course on empiric antibiotics with continued oxygen requirements. Meanwhile, urine Legionella antigen testing returned positive on hospital day four, and after tailoring antibiotics accordingly, the patient's clinical status improved significantly. This case report highlights the efficacy of broad testing in the initial admission and the need for constant re-evaluation in the context of a patient not improving with appropriate therapy.
PubMed: 38854237
DOI: 10.7759/cureus.59979 -
International Journal of Environmental... Oct 2023, the bacterium that causes Legionnaires' disease, can grow and spread in building water systems and devices. The COVID-19 pandemic impacted building water systems...
, the bacterium that causes Legionnaires' disease, can grow and spread in building water systems and devices. The COVID-19 pandemic impacted building water systems through reductions in water usage. growth risk factors can be mitigated through control measures, such as flushing, to address stagnation, as part of a water management program (WMP). A national lodging organization (NLO) provided WMP data, including environmental testing results for periods before and during the pandemic. The statistical analysis revealed an increased risk of water samples testing positive for during the pandemic, with the greatest increase in risk observed at the building's cold-water entry test point. Sample positivity did not vary by season, highlighting the importance of year-round control activities. The NLO's flushing requirements may have prevented an increased risk of growth during the pandemic. However, additional control measures may be needed for some facilities that experience detections. This analysis provides needed evidence for the use of flushing to mitigate the impacts of building water stagnation, as well as the value of routine testing for WMP validation. Furthermore, this report reinforces the idea that WMPs remain the optimal tool to reduce the risk of growth and spread in building water systems.
Topics: United States; Humans; Legionella; Pandemics; COVID-19; Water Microbiology; Legionnaires' Disease; Water Supply; Water; Legionella pneumophila
PubMed: 37835155
DOI: 10.3390/ijerph20196885 -
Respirology Case Reports Feb 2024is the most common cause of Legionnaires' disease in Australasia. species are considered a rare cause of pleural infection, and empyema and lung abscess due to has...
is the most common cause of Legionnaires' disease in Australasia. species are considered a rare cause of pleural infection, and empyema and lung abscess due to has not previously been reported. Our patient presented with a 2-3 week history of breathlessness, lethargy, dry cough and headaches. Initial chest radiograph showed extensive left sided consolidation with an associated pleural effusion. An area of necrotising pneumonia evident on computed tomography scan evolved into a multiloculated intrapulmonary abscess. Sputum culture isolated which prompted culture of pleural fluid on buffered charcoal yeast extract agar and isolation of the organism. This case provides evidence that can cause both empyema and lung abscess, and in areas where it is prevalent, increased use of specific agar for pleural fluid culture should be considered.
PubMed: 38314099
DOI: 10.1002/rcr2.1281